At trick two, why did East switch to a spade from a holding of K9xx (you know that East has the ♠K because he switched to a low spade, indicating interest) rather than continue hearts? The answer is that the ♥K was singleton. Which means that you can count West for 5 hearts and 3 spades.

Your next move should be to cash the ace and king of diamonds, West following twice. You now cross over to the ♣A. Before playing a second round of clubs, you should make the key move of cashing the ♦Q.

If West discards a heart on this trick, then you know that West has 3 clubs to go along with 5 hearts, 3 spades and 2 diamonds. You therefore lead a club to the jack, hoping that East holds the ♣Q.

If West follows to the diamond, however, you should play a club to the nine. If West started with 5 hearts, 3 spades, and 4 diamonds, this means he has a singleton club, and will show out on this trick, allowing your ♣9 to hold, after which you can cross back to the ♥A and take a marked finesse against East's queen by leading a club to the jack. You will end up with 4 clubs, 3 diamonds, 1 heart and 1 spade for nine tricks. If West started with exactly three diamonds, then he has two clubs. If West wins the ♣9 either with the ♣10 or with the ♣Q, he will find himself endplayed into playing a heart away from the queen. You will then be able to ride West's heart return around to the jack, cross back to dummy with the ♥A, and then play a club to the jack (finessing East's marked queen if necessary). Even though you concede a club trick, possibly unnecessarily to West, you will end up with 3 clubs, 3 diamonds, 1 spade and two hearts for nine total tricks.

When this deal was broadcast in Bridge Base Online's vugraph, both declarers failed to find the winning line of play. Both declarers started out identically up to the point where they played a club to dummy's ace, but instead of cashing the ♦Q, they tried for four club tricks by playing a club to the jack. When West won the queen, he was not endplayed as he still had a diamond with which to exit. About one-third of the field made the contract, including Steve Weinstein who took the line recommended here. It is worth noting that by cashing the ♦Q you have not lost anything whatsoever. If West shows out, you haven't lost anything, but if he follows you can ascertain your contract.

Analysis:
A double dummy analysis is not quite appropriate for hand, as knowledge of all four hands make the problem trivial.
Par Contract Analysis:
The par contract on this deal is 3NT by North-South.

Bridge Baron deal No : N1903-58368-66911-27023-25289-89357